Oil burner

ABSTRACT

A gun type oil burner provided with a conventional lily having flow-directing blades which provide a rapidly swirling rotation of air within the blast tube, the improvement involving the provision of a partition plate upstream of the lily to provide a substantial increase in operating pressure upstream thereof, and with jet orifices specifically aligned with the flow-directing surfaces of the lily so as to direct high velocity jets of air on to the flow-directing surfaces in such a way as to maximize the swirl in the blast tube.

United States Patent Flournoy et al.

' 151' 3,656,692 I451 Apr. 18, 1972 1 OIL BURNER [72] inventors: Norman E. Flournoy; Julian H. Dancy, both of Richmond; Raymond Trippet,

Highland Springs, all of Va.

[73] Assignee: Texaco Inc., New York, NY.

[22] .Filed: JIILS, 1971 [21] Appl. No.: 104,044

52 user 219/465 s1] lnt.Cl ..B05b7/l0 [53] Fieltllofsellch 9/405 [56] References Cited UNITED STATES PATENTS 2,146,250 2/1939 DElia "431/265 2,347,594 4/1944 De Lin ..43l/265 2,570,996 10/1951 Walshin ..43l/265 3,278,125 10/1966 Doellinget al ..239/405 Primary Examiner-Lloyd E. King Attorney-Thomas H. Whaley, Carl 0. Ries and L. H. Phelps, Jr. I I

' A gun type oil burner provided with a conventional lily having flow-directing blades which provide a rapidly swirling rotation of air within the blast tube, the improvement involving the provision of a partition plate upstream of the lily to provide a substantial increase in operating pressure upstream thereof,

and with jet orifices specifically aligned with the flow-directing surfaces of the lily so as to direct high velocity jets of air on to the flow-directing surfaces in such a way as to maximize the swirl inthe blast tube.

4 Claims, 6 Drawing Figures PATENTEDAPR 18 new 3,656,692

SHEET 1 [IF v3 SHEET 2 OF 3 PATENTEDAPR 18 1912 FIG.

PATENTEnAPRlame 3,656,692

SHEET 3 OF 3 FIG. .6

OIL BURNER The present invention relates to a gun type oil burner and more particularly involves an improvement on the burner structure disclosed and claimed in U.S. Pat. No. 3,278,125, issued to the same assignee.

More particularly, the burner of the present invention involves an improvement on a known gun type burner described and claimed in U.S. Pat. No. 3,278,125, comprising a blast tube supplied with air by a conventional squirrel cage type blower. The gun type burner on which the present invention constitutes an improvement, includes an air swirler in the blast tube, slightly upstream of the oil atomizing nozzle. The swirler includes a number of vanes so located as to spin or rotate the stream of air about the axis of the blast tube. This tends to cause a uniform distribution of air throughout the blast tube by combining the localized flows, channels, eddies or air, etc., to a uniform stabilized flow. Also, the burner is provided with an exit structure comprising a constricted collar having a number of planar surfaces which definechannels on the upstream face thereof. These, in turn, are so directed as to cause the rotating flow of air to move outwardly in a constricted, tight air swirl.

The present invention is based upon the discovery that the important improvements inherent in the foregoing structure are yet further enhanced and improved by combining the swirl-producing vanes with independent, high-velocity jets or streams of air emanating from a relatively high pressure zone through suitable orifices or nozzles. In other words, by supplying each of the swirl vanes with an independent jet source of air applied directly on to the upstream, swirl-producing surfaces in an axial direction, the spiralling effect seems to be greatly enhanced.

A number of additional advantages are realized, namely and to wit, the avoidance of flow impainnents such as pulsation and the associated mechanical and combustion noises which are associated with radial upsets in the air pressure flow or occasioned by pressure surges andchanges in the combustion chamber.

In order to describe the invention in greater detail reference is made to the figures of the drawing wherein one typical embodiment is illustrated.

FIG. 1 is an elevation facing the burner tip of a gun type burner embodying the principles of the present invention;

. FIG. 2 is a side elevation of the burner shown in FIG. 1;

FIG. 3 is a detail view largely in cross sectionof the burner end or tip of the blast tube shown in FIGS. 1 and 2;

FIG. 4 is a transverse sectional view taken on the line 4-4 of FIG. 3;

FIG. 5 is a detail plan view of the blast tube partition or barrier shown in FIG. 3;

FIG. 6 is a perspective, exploded view of the major elements embodying the tip of the burner, with the blast tube, the spray nozzle, electrodes and associated parts removed to illustrate the relative coaction of the interior members and the function of the gas flow therein.

In describing the present embodiment it is to be noted that the basic structure, including the blast tube, the swirl-producing stabilizer vane and the burner tip are all disclosed and described in detail in U.S. Pat. No. 3,278,125, to which the present invention involves an improvement.

Furthermore, reference is made to that disclosure for full details of such structure, and such disclosure is, by reference, specifically included as a part of the description thereof.

More specifically, blast tube 10 projects from the usual plenum chamber pressurized by internal squirrel cage blower, not shown, as well as a drive motor and other equipment which are universally conventional in this type of burner, and therefore not shown in detail.

FIGS. 3, 4 and 6 disclose the air swirler and stabilizer 11 mounted on'fuel conduit 13 which terminates in fuel nozzle 14, with electrodes 15 projecting from insulators 16.

The air swirler per se comprises four vanes positioned upstream of the fuel nozzle, each of the vanes being shaped to guide a draft of air to the periphery of the blast tube while im parting a spiral motion in the same rotational direction. The

outermost edges of the vanes are spaced a substantial distance radially inwardly from the face of the blast tube and the upstream face of each blade is given a preferably semi-cylindrical surface placed at a suitable swirl angle inthe range of about 40-75, presenting an effective area to the flowing air sufficient to turn substantially the entire mass of air supplied to the vanes into a rapid swirling air mass flow but insuflicient to act appreciably as a restriction or choke. In brief, the function of the vanes, as shown in the aforesaid patent, is to collect a vagrant variety of heterogeneous air flows into a uniform mass flow and to do this without material flow restriction.

Therefore, the benefits of the air stabilizer or swirler include stabilizing other-unsymmetrical flows of air in the blast tube, namely homogenizing the various separate streams and channels of air throughout the dead spots to product a uniform redistribution of rapidly rotating air masses which fill the tube and move forward uniformly which, reaching the endcone, produces a tight swirling mass to produce a mixture with the sprayed fuel.

The end cone structure 29 disclosed more specifically in FIGS. 1, 3 and 6, comprises a series of pyramidal cowls 30 spaced about constricted opening 31, forming a'substantially star shaped configuration. The cowls 30 are shaped so that each ridge line 30a extends downstream and eccentrically with respect to the axis of the blast tube.

The upstream, inner face of the end cone 29, exposed to the spiral air column leaving the swirler comprises a series of planes as shown, creating the cowls and the channels therewithin, thus the interior ridge lines of the channels (parallel to outer ridge lines 30a) which are represented as at 33, are inclined downstream eccentrically of the blast tube axis as aforesaid, making a skewed angle with the radius from about 8-l 6".

In any event, the air is directed in a conical air pattern as a highly directed swirl about the longitudinal axis .of the blast tube and, as. illustrated in FIG. 6, leaves the cone in a downstream direction in a spiral clockwise manner so that the rotating air goes through the cone of fuel spray discharged by the atomizer tip to produce the desired combustible mixture,

Whereas the foregoing constitutes a resume of the development covered by U.S. Pat. No. 3,278,125, the following is more specific to the improvement thereof which constitutes the present invention. More specifically, the blast tube is provided with a partition plate or barrier 40 shown in FIGS. 3, 5 and 6, which extends transversely across the blast tube normal to the axis thereof, and is preferably sealed or snugly fitted into' the interior thereof. Holes 42 are provided to accommodate insulators l6. Aperture 44 is also provided to accommodate the central axial fuel conduit 13. Aside from apertures 46 provided to enable the plate to'be fastened to the stabilizer plate 11, the apertures 48 are provided specifically for the purpose of affording jet orifices to direct controlled, axial streams of air in high velocity form.

Moreover, it is to be noted that each of these orifices 48 is arranged axially opposite a deflecting surface of one of four vanes of the stabilizer 11.

Accordingly, therefore, the purpose of the invention is to afford directed streams of high velocity, high kinetic energy air which are projected axially at the central channel of each of the vanes. This is shown more or less diagrammatically in FIG. 6 wherein one of the jet streams of air 48 is segregated diagrammatically for illustrative purposes. As shown therein, the jet impinges axially into the central lower portion of the inlet channel of the vane opposite which it is located so that the stream isdiverted in the path indicated by the dotted lines 50 and into a swirling motion indicated as at 52.

Manifestly, this stream combines with the other streams from the swirl plate 11 so that the entire effluent thereof, comprising four separate streams merge together in a single mass flow of stabilized air in the blast tube. Moreover, on reaching the tip of the burner, as previously described, the swirls are mass ofair.

is typical.

the barrier plate as shownin the present drawings,

' caught by the inwardly extending channels 33 and, forced inwardly to form a dense, tightly constricted, rapidly swirling in the embodiment shown, pairs of jet orifices 48 are arranged opposite each of the swirl plates. However either multiple or single orifices may be adequate where desired.

A hole 54 in the barrier plate 40 is aligned with aperture 56 in the swirl. plate-11' to hole'58 is arranged to balance the air flow contributed by the peep hole '54, and is also set in a position behind aperture 60 the high velocity jets of air through the orifice's'48. Thus, for example, the typical burner supplied'with a draft of air and employing swirl plates, as for example, in US. Pat. No. 3,278,125, typically involves negligible upstream pressures in the plenum.

On the other hand, the present development manifestly requires plenum pressures which are a high multiple of this, as for namely pressures sufficient to support high velocity air jets,

' with a volume flow, however, which is no greater than that of the burner without the present development.

That is to say, inasmuch as the ultimate ratio of air to fuel will be in the same general category as that of the aforementioned patent bumer(in actuality being somewhat less), the fan must necessarily be modified to operate at such higher pressures but, significantly, at no appreciably greater total air delivery rate. This can be accomplished in many ways but most readilyby simply operating the typical squirrel cage fan blower at a greater" rate, as for example, in the present embodiment at a rate of 3,450 RPM rather than the normal 1,725 RPM.

The results achieved by the present development are readily evident from the comparative results achieved. Typical of these, for example, the results of the operation ofa typical burner (commercially on the market as TexacoModel TWJ 135 A7) firing at the rate of 0.9 gallon per hour into a 100,000 BTU warm air furnace are represented by the following:

- SMOKE'NO. EXCESS AIR 1:

When the same burner is modified simply by. the insertion of having jet apertures of /16 inch diameter with an upstream pressure of 2.0 inch H,O and fires at the rate of 0.9 gph into the same 100,000 BTU warm air furnace, the results are as follows:

EXCESS AIR 96 allow observation of the combustion, flame by a photo electric safety device (not shown). 'A second example 2.0 inch of water and upwardly,,

For example, a pressure equal to 0.4 inch of water ,wardly from the central axis in a shock, all of which otherwise tend to produce pulsations or shocks in the plenum chamber accompanied by what is colloquially referred to as stalling of the fan blade.

- We claim: I

1. In a gun type oil burner comprising in combination a blast tube having a fuel conduit thereinand afuel discharge nozzle adjacent the end of said blast tube, a stabilizer within said blast tube having angled blades'with an eflective .area exposed to flujdflow to direct substantially all of said air. ina downstream swirling motion about the longitudinal axis of said chamber without unduerestriction of fluid flow, and an end cone structure having a central opening at thedischarge end'of said upstream of said stabilizer andseparating the blast tube 6 v into two chambers,- jet orifices in said plate effective to restrict air flow through the blast tube to an extent sulficient to maintain on the upstreamside of saidplate a pressure which is multiple of that on the downstream side of said plate and being sufliciently restricted to formhigh velocity jets of air flowing parallel to the axis of said blast tube, said jet orifices being in axial alignment with the effective flow-directing surfaces of the angle bladesof said stabilizer whereby to selectively direct high velocity jets of air into said flow-directing surfaces.

2. A combination as defined in claim 1 wherein the gauge pressure upstream of said barrier plate is at least four times that of the gauge downstream to provide high energy jetsof air through said orifices.

3. A combination as defined in claim 1 of orifices are located axially opposite blades.

4. In a gun type burner having a blast tube supplied with a high pressure blast of air and a fuel discharge nozzle adjacent the tip thereof, 'and provided with flow stabilizing means, having a plurality of angles blades spaced equally about the axis of said blast tube, adjacent edges of said blades lying in the same plane and being aligned longitudinally, said blades flaring outgenerally downstream direction to provide a spiral flow of air in the blast tube, the outer edges of said blades with respect to said central axis being curved to fon'n a surface of a volume of any cross section such that the straight line generatrix thereof is parallel to the angle of swirl with respect to said support axis, the blade area in normal projection said support axis exposed to the fluid flow occup g the blast tube-without undue restriction to fluid flow therein, the improvement which comprises,

wherein a plurality each of said angle a partition plate extending transversely across the blast tube upstream of said stabilizer and effective to restrict air flow throughthe blast tube sufiiciently to maintain a sub stantially high pressure on the upstream side of said plate,

jet orifices formed in said plate in axial alignment withthe eflective flow-directing surfaces of the angled blades of said stabilizer whereby to selectively direct high velocity jets of air into said flow-directing surfaces,

said orifices being restricted to maintain on the upstream side of said plate said high pressure in the range of at least four times the to maintain said jets of air in high energy range.

* k 1.! i I downstream gauge pressure and sufiicient 

1. In a gun type oil burner comprising in combination a blast tube having a fuel conduit therein and a fuel discharge nozzle adjacent the end of said blast tube, a stabilizer within said blast tube having angled blades with an effective area exposed to fluid flow to direct substantially all of said air in a downstream swirling motion about the longitudinal axis of said chamber without undue restriction of fluid flow, and an end cone structure having a central opening at the discharge end of said chamber with control surfaces on the upstream face of said end cone for directing said swirling air stream through a constriction closely eccentric to said axis, the improvement which comprises a partition plate extending transversely across the blast tube upstream of said stabilizer and separating the blast tube into two chambers, jet orifices in said plate effective to restrict air flow through the blast tube to an extent sufficient to maintain on the upstream side of said plate a pressure which is multiple of that on the downstream side of said plate and being sufficiently restricted to form high velocity jets of air flowing parallel to the axis of said blast tube, said jet orifices being in axial alignment with the effective flowdirecting surfaces of the angle blades of said stabilizer whereby to selectively direct high velocity jets of air into said flow-directing surfaces.
 2. A combination as defined in claim 1 wherein the gauge pressure upstream of said barrier plate is at least four times that of the gauge downstream to provide high energy jets of air through said orifices.
 3. A combination as defined in claim 1 wherein a plurality of orifices are located axially opposite each of said angle blades.
 4. In a gun type burner having a blast tube supplied with a high pressure blast of air and a fuel discharge nozzle adjacent the tip thereof, and provided with flow stabilizing means, having a plurality of angled blades spaced equally about the axis of said blast tube, adjacent edges of said blades lying in the same plane and being aligned longitudinally, said blades flaring outwardly from the central axis in a generally downstream direction to provide a spiral flow of air in the blast tube, the outer edges of said blades with respect to said central axis being curved to form a surface of a volume of any cross section such that the straight line generatrix thereof is parallel to the angle of swirl with respect to said support axis, the blade area in normal projection to said support axis exposed to the fluid flow occupying the blast tube without undue restriction to fluid flow therein, the improvement which comprises, a partition plate extending transversely across the blast tube upstream of said stabilizer and effective to restrict air flow through the blast tube sufficiently to maintain a substantially high pressure on the upstream side of said plate, jet orifices formed in said plate in axial alignment with the effective flow-directing surfaces of the angled blades of said stabilizer whereby to selectively direct high velocity jets of air into said flow-directing surfaces, said orifices being restricted to maintain on the upstream side of said plate said high pressure in the range of at least four times the downstream gauge pressure and sufficient to maintain said jets of air in high energy range. 